Film for Odor Suppression

ABSTRACT

The present disclosure provides a film. In an embodiment, a film for suppressing odors is provided and includes a composition of (A) from 85 wt % to 99 wt % of a thermoplastic polymer and (B) from 15 wt % to 1 wt % of an odor suppressant. The odor suppressant is a blend composed of (Bi) particles of zinc oxide and (Bii) zinc ionomer. The zinc oxide particles (Bi) have a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m 2 /g to 9 m 2 /g, and a porosity less than 0.020 m 3 /g. The composition has a methyl mercaptan odor suppression value less than 70 at 3 days exposure to methyl mercaptan as measured in accordance with ASTM D5504-12.

BACKGROUND

Many uses of articles made from thermoplastic polymer encounter thenuisance of foul odor. Common sources of offending odor include hydrogensulfide (H₂S) emitting compositions and thiol-containing compositions.Many applications exist where it is desirable for thermoplastic polymerarticle to be able to remove, or otherwise suppress, odor. As such,numerous industries desire materials that can remove sulfur-basedodorants such as H₂S, mercaptans, and thiols from the gas phase. Acommon example is the ability of a plastic trash bag liner (i.e., anolefin-based polymer article) to be able to remove odor.

Zinc oxide (ZnO) particles and zinc salts are known to consume manyodor-generating molecules such as H₂S and mercaptans. All other factorsbeing equal, it is known that ZnO concentration and odor suppression aredirectly related—i.e., as ZnO concentration increases in a givenolefin-based polymer article, the effectiveness of odor suppression alsoincreases.

Although odor suppression increases as ZnO increases, limits do existfor the amount of ZnO that can be effectively incorporated intothermoplastic polymer, and olefin-based polymer articles in particular.In the production of blown film trash liners for example, high loadingof ZnO particles increases extrusion die lip buildup, thereby causingfilm defects. High loading of ZnO particles also increases hazeresulting in degradation of olefin-based polymer film transparencyand/or degradation in film color. High loading of ZnO particles alsodeleteriously impacts mechanical properties such as impact strength andfilm tear strength. Processing parameters and end-use mechanicalrequirements thereby impose practical limits to the load of ZnOparticles into thermoplastic polymers, and olefin-based polymercompositions.

A need therefore exists for thermoplastic polymer compositions withimproved odor suppression while simultaneously carrying suitable zincload in order to maintain processability, desired optics, and desiredmechanical properties for end-use applications. A need further existsfor odor-suppressing articles made from such thermoplastic polymercompositions.

SUMMARY

The present disclosure provides a film. In an embodiment, a film forsuppressing odors is provided and includes a composition of (A) from 85wt % to 99 wt % of a thermoplastic polymer and (B) from 15 wt % to 1 wt% of an odor suppressant. The odor suppressant is a blend composed of(Bi) particles of zinc oxide and (Bii) zinc ionomer. The zinc oxideparticles (Bi) have a D50 particle size from 100 nm to 3000 nm, asurface area from 1 m²/g to 9 m²/g, and a porosity less than 0.020 m³/g.The composition has a methyl mercaptan odor suppression value less than70 at 3 days exposure to methyl mercaptan as measured in accordance withASTM D5504-12.

Definitions

Any reference to the Periodic Table of Elements is that as published byCRC Press, Inc., 1990-1991. Reference to a group of elements in thistable is by the new notation for numbering groups.

For purposes of United States patent practice, the contents of anyreferenced patent, patent application or publication are incorporated byreference in their entirety (or its equivalent U.S. version is soincorporated by reference) especially with respect to the disclosure ofdefinitions (to the extent not inconsistent with any definitionsspecifically provided in this disclosure) and general knowledge in theart.

The numerical ranges disclosed herein include all values from, andincluding, the lower and upper value. For ranges containing explicitvalues (e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between anytwo explicit values is included (e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5to 6; etc.).

Unless stated to the contrary, implicit from the context, or customaryin the art, all parts and percents are based on weight and all testmethods are current as of the filing date of this disclosure.

An “agglomerate” is a plurality of individual fine solid particlesclumped or otherwise together forming a single mass.

The terms “blend” or “polymer blend,” as used herein, is a blend of twoor more polymers. Such a blend may or may not be miscible (not phaseseparated at molecular level). Such a blend may or may not be phaseseparated. Such a blend may or may not contain one or more domainconfigurations, as determined from transmission electron spectroscopy,light scattering, x-ray scattering, and other methods known in the art.

The term “composition” refers to a mixture of materials which comprisethe composition, as well as reaction products and decomposition productsformed from the materials of the composition.

The terms “comprising,” “including,” “having” and their derivatives, arenot intended to exclude the presence of any additional component, stepor procedure, whether or not the same is specifically disclosed. Inorder to avoid any doubt, all compositions claimed through use of theterm “comprising” may include any additional additive, adjuvant, orcompound, whether polymeric or otherwise, unless stated to the contrary.In contrast, the term “consisting essentially of” excludes from thescope of any succeeding recitation any other component, step, orprocedure, excepting those that are not essential to operability. Theterm “consisting of” excludes any component, step, or procedure notspecifically delineated or listed. The term “or,” unless statedotherwise, refers to the listed members individually as well as in anycombination. Use of the singular includes use of the plural and viceversa.

An “ethylene-based polymer” is a polymer that contains more than 50weight percent (wt %) polymerized ethylene monomer (based on the totalamount of polymerizable monomers) and, optionally, may contain at leastone comonomer. Ethylene-based polymer includes ethylene homopolymer, andethylene copolymer (meaning units derived from ethylene and one or morecomonomers). The terms “ethylene-based polymer” and “polyethylene” maybe used interchangeably. Nonlimiting examples of ethylene-based polymer(polyethylene) include low density polyethylene (LDPE) and linearpolyethylene. Nonlimiting examples of linear polyethylene include linearlow density polyethylene (LLDPE), ultra low density polyethylene(ULDPE), very low density polyethylene (VLDPE), multi-componentethylene-based copolymer (EPE), ethylene/α-olefin multi-block copolymers(also known as olefin block copolymer (OBC)), substantially linear, orlinear, plastomers/elastomers, and high density polyethylene (HDPE).Generally, polyethylene may be produced in gas-phase, fluidized bedreactors, liquid phase slurry process reactors, or liquid phase solutionprocess reactors, using a heterogeneous catalyst system, such asZiegler-Natta catalyst, a homogeneous catalyst system, comprising Group4 transition metals and ligand structures such as metallocene,non-metallocene metal-centered, heteroaryl, heterovalent aryloxyether,phosphinimine, and others. Combinations of heterogeneous and/orhomogeneous catalysts also may be used in either single reactor or dualreactor configurations.

“Ethylene plastomers/elastomers” are substantially linear, or linear,ethylene/α-olefin copolymers containing homogeneous short-chainbranching distribution comprising units derived from ethylene and unitsderived from at least one C₃-C₁₀ α-olefin comonomer. Ethyleneplastomers/elastomers have a density from 0.870 g/cc to 0.917 g/cc.Nonlimiting examples of ethylene plastomers/elastomers include AFFINITY™plastomers and elastomers (available from The Dow Chemical Company),EXACT™ Plastomers (available from ExxonMobil Chemical), Tafmer™(available from Mitsui), Nexlene™ (available from SK Chemicals Co.), andLucene™ (available from LG Chem Ltd.).

“High density polyethylene” (or “HDPE”) is an ethylene homopolymer or anethylene/α-olefin copolymer with at least one C₄-C₁₀ α-olefin comonomer,or C₄-C₈ α-olefin comonomer and a density from 0.940 g/cc, or 0.945g/cc, or 0.950 g/cc, or 0.953 g/cc to 0.955 g/cc, or 0.960 g/cc, or0.965 g/cc, or 0.970 g/cc, or 0.975 g/cc, or 0.980 g/cc. The HDPE can bea monomodal copolymer or a multimodal copolymer. A “monomodal ethylenecopolymer” is an ethylene/C₄-C₁₀ α-olefin copolymer that has onedistinct peak in a gel permeation chromatography (GPC) showing themolecular weight distribution. A “multimodal ethylene copolymer” is anethylene/C₄-C₁₀ α-olefin copolymer that has at least two distinct peaksin a GPC showing the molecular weight distribution. Multimodal includescopolymer having two peaks (bimodal) as well as copolymer having morethan two peaks. Nonlimiting examples of HDPE include DOW™ High DensityPolyethylene (HDPE) Resins (available from The Dow Chemical Company),ELITE™ Enhanced Polyethylene Resins (available from The Dow ChemicalCompany), CONTINUUM™ Bimodal Polyethylene Resins (available from The DowChemical Company), LUPOLEN™ (available from LyondellBasell), as well asHDPE products from Borealis, Ineos, and ExxonMobil.

An “interpolymer” is a polymer prepared by the polymerization of atleast two different monomers. This generic term includes copolymers,usually employed to refer to polymers prepared from two differentmonomers, and polymers prepared from more than two different monomers,e.g., terpolymers, tetrapolymers, etc.

“Linear low density polyethylene” (or “LLDPE”) is a linearethylene/α-olefin copolymer containing heterogeneous short-chainbranching distribution comprising units derived from ethylene and unitsderived from at least one C₃-C₁₀ α-olefin, or C₄-C₈ α-olefin, comonomer.LLDPE is characterized by little, if any, long chain branching, incontrast to conventional LDPE. LLDPE has a density from 0.910 g/cc toless than 0.940 g/cc. Nonlimiting examples of LLDPE include TUFLIN™linear low density polyethylene resins (available from The Dow ChemicalCompany), DOWLEX™ polyethylene resins (available from the Dow ChemicalCompany), and MARLEX™ polyethylene (available from Chevron Phillips).

“Low density polyethylene” (or “LDPE”) consists of ethylene homopolymer,or ethylene/α-olefin copolymer comprising at least one C₃-C₁₀ α-olefin,or C₄-C₈α-olefin, that has a density from 0.915 g/cc to less than 0.940g/cc and contains long chain branching with broad MWD. LDPE is typicallyproduced by way of high pressure free radical polymerization (tubularreactor or autoclave with free radical initiator). Nonlimiting examplesof LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell),as well as LDPE products from Borealis, Ineos, ExxonMobil, and others.

“Multi-component ethylene-based copolymer” (or “EPE”) comprises unitsderived from ethylene and units derived from at least one C₃-C₁₀α-olefin, or C₄-C₈ α-olefin, comonomer, such as described in patentreferences U.S. Pat. Nos. 6,111,023; 5,677,383; and 6,984,695. EPEresins have a density from 0.905 g/cc to 0.962 g/cc. Nonlimitingexamples of EPE resins include ELITE™ enhanced polyethylene (availablefrom The Dow Chemical Company), ELITE AT™ advanced technology resins(available from The Dow Chemical Company), SURPASS™ Polyethylene (PE)Resins (available from Nova Chemicals), and SMART™ (available from SKChemicals Co.).

An “olefin-based polymer” or “polyolefin” is a polymer that containsmore than 50 weight percent polymerized olefin monomer (based on totalamount of polymerizable monomers), and optionally, may contain at leastone comonomer. Nonlimiting examples of an olefin-based polymer includeethylene-based polymer or propylene-based polymer.

A “polymer” is a compound prepared by polymerizing monomers, whether ofthe same or a different type, that in polymerized form provide themultiple and/or repeating “units” or “mer units” that make up a polymer.The generic term polymer thus embraces the term homopolymer, usuallyemployed to refer to polymers prepared from only one type of monomer,and the term copolymer, usually employed to refer to polymers preparedfrom at least two types of monomers. It also embraces all forms ofcopolymer, e.g., random, block, etc. The terms “ethylene/α-olefinpolymer” and “propylene/α-olefin polymer” are indicative of copolymer asdescribed above prepared from polymerizing ethylene or propylenerespectively and one or more additional, polymerizable α-olefin monomer.It is noted that although a polymer is often referred to as being “madeof” one or more specified monomers, “based on” a specified monomer ormonomer type, “containing” a specified monomer content, or the like, inthis context the term “monomer” is understood to be referring to thepolymerized remnant of the specified monomer and not to theunpolymerized species. In general, polymers herein are referred to hasbeing based on “units” that are the polymerized form of a correspondingmonomer.

A “propylene-based polymer” is a polymer that contains more than 50weight percent polymerized propylene monomer (based on the total amountof polymerizable monomers) and, optionally, may contain at least onecomonomer. Propylene-based polymer includes propylene homopolymer, andpropylene copolymer (meaning units derived from propylene and one ormore comonomers). The terms “propylene-based polymer” and“polypropylene” may be used interchangeably. Nonlimiting examples ofsuitable propylene copolymers include propylene impact copolymer andpropylene random copolymer.

“Ultra low density polyethylene” (or “ULDPE”) and “very low densitypolyethylene” (or “VLDPE”) each is a linear ethylene/α-olefin copolymercontaining heterogeneous short-chain branching distribution comprisingunits derived from ethylene and units derived from at least one C₃-C₁₀α-olefin comonomer. ULDPE and VLDPE each has a density from 0.885 g/ccto 0.915 g/cc. Nonlimiting examples of ULDPE and VLDPE include ATTANE™ultra low density polyethylene resins (available from The Dow ChemicalCompany) and FLEXOMER™ very low density polyethylene resins (availablefrom The Dow Chemical Company).

TEST METHODS

D10, D50, and D90 particle size is measured using a Coulter LS 230 LaserLight Scattering Particle Sizer, available from Coulter Corporation. D10particle size is the particle diameter at which 10% of the powder's massis composed of particles with a diameter less than this value. D50particle size is the particle diameter at which 50% of the powder's massis composed of particles with a diameter less than this value and 50% ofthe power's mass is composed of particles with a diameter greater thansaid value. D90 particle size is the particle diameter at which 90% ofthe powder's mass is composed of particles with a diameter less thanthis value. Mean volume average particle size is measured using aCoulter LS 230 Laser Light Scattering Particle Sizer, available fromCoulter Corporation. Particle size distribution is calculated inaccordance with Equation A:

$\begin{matrix}{{{Particle}\mspace{14mu} {size}\mspace{14mu} {distribution}} = {\frac{\left( {{D\; 90} - {D\; 10}} \right)}{D\; 50}.}} & {{Equation}\mspace{14mu} A}\end{matrix}$

Dart impact strength is measured in accordance with ASTM D1709, withresults reported in grams (g).

Density is measured in accordance with ASTM D792, Method B. The resultis recorded in grams per cubic centimeter (g/cc).

Differential Scanning Calorimetry (DSC).

Differential Scanning calorimetry (DSC) can be used to measure themelting, crystallization, and glass transition behavior of a polymerover a wide range of temperatures. For example, the TA Instruments Q1000DSC, equipped with an RCS (refrigerated cooling system) and anautosampler is used to perform this analysis. During testing, a nitrogenpurge gas flow of 50 ml/min is used. Each sample is melt pressed into athin film at about 175° C.; the melted sample is then air-cooled to roomtemperature (about 25° C.). A 3-10 mg, 6 mm diameter specimen isextracted from the cooled polymer, weighed, placed in a light aluminumpan (ca 50 mg), and crimped shut. Analysis is then performed todetermine its thermal properties.

The thermal behavior of the sample is determined by ramping the sampletemperature up and down to create a heat flow versus temperatureprofile. First, the sample is rapidly heated to 180° C. and heldisothermal for 3 minutes in order to remove its thermal history. Next,the sample is cooled to −40° C. at a 10° C./minute cooling rate and heldisothermal at −40° C. for 3 minutes. The sample is then heated to 180°C. (this is the “second heat” ramp) at a 10° C./minute heating rate. Thecooling and second heating curves are recorded. The cool curve isanalyzed by setting baseline endpoints from the beginning ofcrystallization to −20° C. The heat curve is analyzed by settingbaseline endpoints from −20° C. to the end of melt. The valuesdetermined are extrapolated onset of melting, Tm, and extrapolated onsetof crystallization, Tc. Heat of fusion (H_(f)) (in Joules per gram), andthe calculated % crystallinity for polyethylene samples using thefollowing Equation: % Crystallinity=((H_(f))/292 J/g)×100. Glasstransition temperature, Tg, is determined from the DSC heating curvewhere half the sample has gained the liquid heat capacity as describedin Bernhard Wunderlich, The Basis of Thermal Analysis, in ThermalCharacterization of Polymeric Materials 92, 278-279 (Edith A. Turi ed.,2d ed. 1997). Baselines are drawn from below and above the glasstransition region and extrapolated through the Tg region. Thetemperature at which the sample heat capacity is half-way between thesebaselines is the Tg.

Elmendorf tear (or tear) is measured in accordance with ASTM D1922-15,machine direction (MD) with results reported in grams-force (gf).

Melt flow rate (MFR) in g/10 min is measured in accordance with ASTMD1238 (230° C./2.16 kg).

Melt index (MI) (I2) in g/10 min is measured in accordance with ASTMD1238 (190° C./2.16 kg).

Morphology.

Polymer morphology (and the zinc ionomer/zinc oxide domain size inparticular) is determined by way of microscopy utilizing an opticalmicroscope (OM) and a scanning electron microscope (SEM).

A. Sample Preparation

OM and SEM—The films are examined as received and also cryogenicallycross sectioned using a diamond knife at −80° C. on a Leica UC7microtome equipped with an FC7 cryosectioning chamber. Film crosssections of approximately 5 microns in thickness are placed on a glassslide containing immersion oil and covered with a glass cover slip. ForSEM examination the cryopolished film cross sections are placed onaluminum sample mounts and sputtered with an Iridium plasma using anEmitech K575X turbo sputter coater for 20 seconds to render samplesconductive for scanning electron microscopy.

B. Techniques

OM—An Olympus Vanox research microscope is used under transmittedNomarski to capture images from cross sections. A Leica MZ-16 stereomicroscope is also used under transmitted and reflected illumination.Images are captured using Olympus Stream digital software.

SEM/EDX—An FEI Nano600 scanning electron microscope operated at a 10 kVaccelerating voltage to capture secondary and backscatter electronimages (SEI and BEI).

Odor Suppression/Odor Suppression Value.

Odor suppression is the ability of a composition to neutralize, orotherwise reduce, the amount of volatile sulfur-containing compounds. Inthe present disclosure, the odor suppression for methyl mercaptan ismeasured with two-dimensional gas chromatography coupled withtime-of-flight mass spectrometry (GCxGC/TOFMS) in accordance with ASTMD5504-12. A control sample is prepared by placing a film formed fromDOWLEX 2085G, ethylene/octene LLDPE, into a Tedlar® bag (polyvinylfluoride). The Tedlar® bag for the control is subsequently filled with aknown amount of methyl mercaptan in a helium gas carrier and the Tedlar®bag is closed. Test samples are prepared by placing a film formed fromrespective test compositions, each test film placed into a respectiveTedlar® bag. Each Tedlar® bag is subsequently filled with a known amountof methyl mercaptan in a helium gas carrier and the Tedlar® bag isclosed. GC samples are taken at pre-determined time intervals from eachbag in order to evaluate odor suppression capability. An odorsuppression value (OSV) is calculated for each test sample by dividingthe test sample methyl mercaptan concentration by the LLDPE controlmethyl mercaptan concentration. The odor suppression value for each testsample is reported as a percentage of methyl mercaptan concentration forthe control film.

The odor suppression test is performed as set forth below.

Sample Preparation:

1. Films are formed by cutting 1.0 g of film into strips (approximately1 cm×30 cm).

2. Each film is inserted into a respective Tedlar® bag, one film perbag. The Tedlar® bag is SKC 1 L sample bag (SKC Tedlar® Sample Bag, 1Liter, Cat No. 232-01).

3. Unscrew the valve from the Tedlar® bag, insert the film strip intothe bag through the valve opening with the handle of a cotton tippedapplicator. Install the valve back onto the sample bag, squeeze air outof bag before tightening the valve to seal the bag.

4. The Tedlar® bag is filled with 0.98 L Helium (AirGas, Ultra GradeHelium).

5. Using a gas-tight glass syringe, each helium filled Tedlar® bag isinjected with 20 mL of helium gas carrying 1000 ppmv methyl mercaptan.

6. 0.50 mL gas sample is removed from each Tedlar® bag at predeterminedtime intervals.

7. Each 0.50 mL gas sample is injected into the GCxGC/TOFMS to analyzemethyl mercaptan concentration. Gas chromatograph: Agilent Model 6890,equipped with a LECO thermal desorption GCxGC modulator and splitinjection port, available from Agilent Technologies, 2850 CentervilleRoad, Wilmington, Del. 19808, or equivalent. Detector: LECO PegasusTime-of-Flight Mass Spectrometer (TOFMS), available from LECOCorporation, 3000 Lakeview Avenue, Saint Joseph, Mich. 49085, orequivalent. Chromatography data system: LECO ChromaTOF 4D software,available from LECO Corporation, or equivalent. Columns: Primary column:Supelco Petrocol DH, 50 m×0.25 mm ID, 0.50 μm, secondary column: AgilentDB-1701, 1.5 m×0.10 mm ID, 0.10 μm film thickness. The secondary columnis in the main GC oven. GCxGC Modulation: Second dimension separationtime: 3 sec, hot pulse time: 0.40 sec, cool time between stages: 1.10sec. Modulator temperature offset: 15° C. above the primary oven.Carrier Gas: Helium, 1.5 mL/min with corrected constant flow viapressure ramps. Inlet: Restek Siltek deactivated 4.0 mm ID PrecisionInlet Liner w/Wool, Cat. #21023-213.5, available from Restek, orequivalent. Split injection mode, split ratio: 30:1, temperature: 250°C.

8. Injection volume: 0.50 mL gas sample by a gas-tight glass syringe.Oven Temperature: Primary GC Oven: 40° C., 8 min. Secondary Oven: Off(not in use). LECO TOFMS Detector: Low Mass: 20; High Mass: 150;Acquisition Rate: 100 Hz; Detector Voltage: 1650 Volts; Electron Energy:−70 Volts; Mass detect Mode: Auto; Transfer Line: 250° C.; Ion Source:200° C.; Solvent Delay: 0 minutes.

9. Odor suppression calculation. Odor suppression=(Concentration gas insample test bag (sample film) at day X)/(concentration gas in test bagwith control film at day X)*100.

A nonlimiting example OSV calculation is provided. At three days thepeak area for GC peak area for methylmercaptan in the control sample is119221, whereas the GC peak area for sample film is 30566 (both inarbitrary units). The odor suppression value for the sample is(30566/119221)*100=57.8. A calibration curve is generated to correlateconcentration of methylmercaptan to GC peak area for methylmercaptan. Assuch, methylmercaptan GC peak area or concentration of methylmercaptancan be used to calculate an odor suppression value, wherein peak areasare compared to peak areas, and concentrations are compared toconcentrations.

Porosity and Surface Area.

Brunauer-Emmett-Teller (BET) porosity and surface area analysis areperformed using a Micromeritics Accelerated Surface Area & Porosimetryinstrument (ASAP 2420). The sample is out-gassed at 105° C. while undervacuum prior to analysis.

The ASAP 2420 instrument employs a static (volumetric) method of dosingsamples and measures the quantity of gas that can be physically adsorbed(physisorbed) on a solid at liquid nitrogen temperature. For themulti-point BET measurement the volume of nitrogen uptake is measured atpre-selected relative pressure points at constant temperature. Therelative pressure is the ratio of the applied nitrogen pressure to thevapor pressure of nitrogen at the analysis temperature of 77 Kelvin (K).Results for porosity are reported in cubic meters per gram, or m³/g.Results for surface area are reported in square meters per gram, orm²/g.

Zinc—Total Amount.

The total amount of zinc present in a composition is determined withx-ray fluorescence spectrometry (XRS), in accordance with ASTM D6247.Results are reported in parts per million, or ppm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a scanning electron microscope (SEM) image of a prior artcomposition containing a polyethylene with zinc oxide particlesdispersed therein.

FIG. 2 is a SEM image of a composition containing an olefin-basedpolymer and an odor suppressant dispersed therein, in accordance with anembodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides a film. In an embodiment, a film forsuppressing odors is provided and includes a composition of (A) from 85wt % to 99 wt % of a thermoplastic polymer and (B) from 15 wt % to 1 wt% of an odor suppressant. The odor suppressant is a blend composed of(Bi) particles of zinc oxide and (Bii) zinc ionomer. The zinc oxideparticles (Bi) have a D50 particle size from 100 nm to 3000 nm, asurface area from 1 m²/g to 9 m²/g, and a porosity less than 0.020 m³/g.The composition has a methyl mercaptan odor suppression value less than70 at 3 days exposure to methyl mercaptan as measured in accordance withASTM D5504-12.

The present film includes a thermoplastic polymer. A “thermoplasticpolymer,” as used herein, is a polymeric material which can berepeatedly softened and made flowable when heated and returned to a hardstate when cooled to room temperature. Thermoplastic polymeric materialgenerally has an elastic modulus greater than 10,000 psi (68.95 MPa)using the method of ASTM D638-72. In addition, thermoplastics can bemolded or extruded into articles of any predetermined shape when heatedto the softened state. Nonlimiting examples of thermoplastic polymersinclude olefin-based polymer, ethylene-based polymer, propylene-basedpolymer, polystyrene, ethylene vinyl acetate (EVA), nylon, polyester,ethylene vinyl alcohol (EVOH), and combinations thereof.

A. Olefin-Based Polymer

In an embodiment, the thermoplastic polymer is an olefin-based polymer.The olefin-based polymer can be a propylene-based polymer or anethylene-based polymer. Nonlimiting examples of propylene-based polymersinclude propylene copolymer, propylene homopolymer, and combinationsthereof. In an embodiment, the propylene-based polymer is apropylene/α-olefin copolymer. Nonlimiting examples of suitable α-olefinsinclude C₂ and C₄-C₂₀ α-olefins, or C₄-C₁₀ α-olefins, or C₄-C₈α-olefins. Representative α-olefins include ethylene, 1-butene,1-pentene, 1-hexene, 1-heptene and 1-octene.

In an embodiment, the propylene/α-olefin copolymer is apropylene/ethylene copolymer containing greater than 50 wt % unitsderived from propylene, or from 51 wt %, or 55 wt %, or 60 wt % to 70 wt%, or 80 wt %, or 90 wt %, or 95 wt %, or 99 wt % units derived frompropylene, based on the weight of the propylene/ethylene copolymer. Thepropylene/ethylene copolymer contains a reciprocal amount of unitsderived from ethylene, or from less than 50 wt %, or 49 wt %, or 45 wt%, or 40 wt % to 30 wt %, or 20 wt %, or 10 wt %, or 5 wt %, or 1 wt %,or 0 wt % units derived from ethylene, based on the weight of thepropylene/ethylene copolymer.

In an embodiment, the olefin-based polymer is an ethylene-based polymer.The ethylene-based polymer can be an ethylene homopolymer or anethylene/α-olefin copolymer.

In an embodiment, the ethylene-based polymer is an ethylene/α-olefincopolymer. Nonlimiting examples of suitable α-olefins include C₃-C₂₀α-olefins, or C₄-C₁₀ α-olefins, or C₄-C₈ α-olefins. Representativeα-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-hepteneand 1-octene.

In an embodiment, the ethylene/α-olefin copolymer is an LLDPE that is anethylene/C₄-C₈ α-olefin copolymer. The LLDPE has one, some, or all ofthe following properties:

(i) a density from 0.910 g/cc to 0.930 g/cc; and/or

(ii) a Tm from 121° C. to 123° C.; and/or

(iii) a melt index from 0.5 g/10 min to 1.0 g/10 min.

A nonlimiting example of a suitable LLDPE is DOWLEX 2085 available fromThe Dow Chemical Company.

B. Odor Suppressant

The present composition includes an odor suppressant. The odorsuppressant is a blend of zinc oxide (“ZnO”) particles (Bi) and a zincionomer (Bii).

B(i) Zinc Oxide

The odor suppressant includes particles of zinc oxide (or “ZnO”). TheZnO particles have a D50 particle size from 100 nm to 3000 nm, a surfacearea from 1 m²/g to less than 10 m²/g, and a porosity less than 0.020m³/g.

In an embodiment, the ZnO particles have one, some, or all of thefollowing properties (i)-(iii) below:

(i) a particle size D50 from 100 nm, or 200 nm, or 300 nm, or 400 nm to500 nm, or 600 nm, or 700 nm, or 800 nm, or 900 nm, or 1000 nm, or 2000nm, or 3000 nm; and/or

(ii) a surface area from 1 m²/g, or 2 m²/g, or 3 m²/g, or 4 m²/g to 5m²/g, or 6 m²/g, or 7 m²/g, or 8 m²/g, or 9 m²/g; and/or

(iii) a porosity from 0.005 m³/g, or 0.006 m³/g, or 0.008 m³/g, or 0.010m³/g to 0.012 m³/g, or 0.013 m³/g, or 0.015 m³/g, or less than 0.020m³/g.

Nonlimiting examples of suitable ZnO particles include Zochem 102,Zochem 104 from Zochem Inc., and ZnO particles available from USResearch Nanoparticles.

B(ii) Zinc Ionomer

The odor suppressant includes a zinc ionomer. The term “zinc ionomer,”(or “ZnI/O”) as used herein, refers to a copolymer based on a zinc saltof a copolymer of ethylene and a vinyl comonomer with an acid group.Nonlimiting examples of suitable comonomers having vinyl comonomer withan acid group include methyl/methacrylic acid, vinyl acrylic acid,methacrylate, n-butyl acrylic acid, and acrylic acid.

The zinc ionomer is a cross-linked polymer in which the linkages areionic (i.e., interchain ionic bonding) as well as covalent bonds. Thezinc ionomer has positively and negatively charged groups, which are notassociated with each other, providing the zinc ionomer with a polarcharacter.

Nonlimiting examples of suitable zinc ionomers include zinc salt ofethylene/acrylic acid comonomer, zinc salt ofethylene/methyl-methacrylic acid copolymer, zinc salt of ethylene/vinylacrylic acid copolymer, zinc salt of ethylene/methacrylate copolymer,zinc salt of ethylene/n-butyl acrylic acid copolymer, and anycombination thereof.

In an embodiment, the zinc ionomer is a zinc salt of ethylene/acrylicacid copolymer. A nonlimiting example of a suitable zinc ionomer isAMPLIFY I/O 3701 available from The Dow Chemical Company.

C. Composition

The present composition includes (A) from 85 wt % to 99 wt % of thethermoplastic polymer and (B) from 15 wt % to 1 wt % of the odorsuppressant. In an embodiment, the thermoplastic polymer is theolefin-based polymer. The odor suppressant is mixed, or otherwiseblended into the olefin-based polymer matrix. The odor suppressant is ablend of (Bi) particles of zinc oxide (ZnO) and (Bii) zinc ionomer(ZnI/O). The zinc oxide particles have a D50 particle size from 100 nmto 3000 nm, a surface area from 1 m²/g to 9 m²/g, and and a porosityless than 0.020 m³/g and is hereafter referred to as Composition 1.Composition 1 has a methyl mercaptan odor suppression value less than 70at 3 days exposure to methyl mercaptan.

The odor suppressant is present in an amount from 1 wt % to 15 wt % ofComposition 1 (based on total weight of Composition 1), and the ratio ofZnO to ZnI/O (hereafter “ZnO— to ZnI/O ratio”) is from 3:1 to 1:7 basedon the weight of the odor suppression. The ZnO— to ZnI/O ratio can befrom 3:1, or 2:1, or 1:1 to 1:2, or 1:3, or 1:4, or 1:5, or 1:6, or 1:7.

In an embodiment, the present composition includes from 85 wt %, or 90wt % to 95 wt %, or 97 wt %, or 99 wt % component (A) that is anethylene-based polymer. The present composition includes a reciprocalamount of component (B), or from 15 wt %, or 10 wt % to 5 wt %, or 3 wt%, or 1 wt % odor suppressant wherein the ZnO— to ZnI/O ratio is from1:3, or 1:4, or 1:5 to 1:6, or 1:7. The zinc oxide particles (Bi) have aD50 particle size from 100 nm, or 200 nm, or 300 nm, or 400 nm to 500nm, or 600 nm, or 700 nm, or 800 nm, or 900 nm, or 1000 nm, or 2000 nm,3000 nm. The zinc oxide particles also have a surface area from 1 m²/g,or 2 m²/g, or 3 m²/g to 4 m²/g, or 5 m²/g, or 6 m²/g, and the zinc oxideparticles also have a porosity from 0.0050 m³/g, or 0.0070 m³/g, or0.0090 m³/g to 0.010 m³/g, or 0.013 m³/g to 0.015 m³/g and thecomposition is hereafter referred to as Composition 2. Composition 2 hasa methyl mercaptan odor suppression value of less than or equal to 55 at3 days of exposure to methyl mercaptan.

In an embodiment, Composition 2 contains from 1000 ppm, or 5000 ppm, or10000 ppm, or 20000 to 30000 ppm, or 40000 ppm, or 50000 ppm, or 60000ppm, or 90000 ppm total zinc. The term “total zinc,” as used herein, isthe aggregate of zinc metal from the zinc oxide (Bi) and the zincionomer (Bii).

In an embodiment, Composition 2 contains from 0.5 wt %, or 1.0 wt %, or2.0 wt %, or 3.0 wt % to 4.0 wt %, or 5.0 wt %, or 6.0 wt % total zinc.

In an embodiment, the ethylene-based polymer (A) is present in thecomposition to the exclusion of any other polymer (with exception of theZnI/O in the odor suppression). In other words, the ethylene-basedpolymer is the sole polymeric component (the only polymeric component)in the composition other than the zinc ionomer. In a further embodiment,the sole polymeric component is an LLDPE (other than the zinc ionomer).

In an embodiment, the total zinc is present in Composition 2 to theexclusion of International Union of Pure and Applied Chemistry (IUPAC)Group 5 metals to IUPAC Group 12 metals. The term “from Group 5 metalsto Group 12 metals,” as used herein, includes IUPAC Group 5 metals(Chemical Abstracts Service [CAS] VB), IUPAC Group 6 metals (CAS VIB),IUPAC Group 7 metals (CAS VIIB), IUPAC Group 8 metals (CAS VIIIB), IUPACGroup 9 metals (CAS VIIIB), IUPAC Group 10 metals (CAS VIIIB), IUPACGroup 11 metals (CAS 1B), IUPAC Group 12 metals (CAS IIB). It isunderstood that zinc is a Group 12 metal, with the exclusion applying tocadmium and mercury. The term “total zinc is present to the exclusion ofother Group 5 to Group 12 metals,” as used herein, refers to thepresence of zinc and the absence of Group 5 to Group 12 metals in thecomposition, whereby the composition contains from 0 ppm, or fromgreater than 0 ppm, or 1 ppm, or 2 ppm to 3 ppm Group 5 metal to Group12 metal.

In an embodiment, Composition 2 is a heterophasic composition andincludes a continuous-phase composed of the ethylene-based polymer,component (A) and a discontinuous-phase of component (B). Thediscontinuous phase is in the form of discrete domains. The domains arecomposed of the zinc oxide particles embedded in the zinc ionomer. Thedomains (zinc ionomer with ZnO particles embedded therein) have anaverage diameter from 500 nm to 1000 nm, or 3000 nm to 5,000 nm, or7,500 nm, or 10,000 nm as measured in accordance with OM/SEM microscopy.

Applicant discovered Composition 2 having an odor suppressant with ZnO—to ZnI/O ratio from 1:3 to 1:7, ZnO with (i) D50 particle size from 100nm to 3000 nm (ii) surface area, from 1 m²/g to 6 m²/g, and (iii)porosity from 0.005 m³/g to 0.015 m³/g yields unexpected improvement inodor suppression. The domains are homogeneously dispersed in acontinuous phase composed of the ethylene-based polymer.

D. Applications

The present film may be used in any application wherein a thermoplasticpolymeric material, and an olefin-based polymer in particular, isexposed to mercaptans, H₂S, disulfides or amines. Nonlimiting examplesof suitable applications for the present film include trash liners,poultry diapers, ostomy bags, mattresses, mattress covers, poultrypackaging, automotive interior parts, carpet fibers, and carpet backing.

E. Film

The film is composed of, or is otherwise formed from the presentcomposition. The film includes the present composition, the presentcomposition composed of (A) from 85 wt % to 99 wt % of a thermoplasticpolymer and (B) from 15 wt % to 1 wt % of the odor suppressant. The odorsuppressant is a blend composed of (i) particles of zinc oxide and (ii)a zinc ionomer. The zinc oxide particles have a D50 particle size from100 nm to 3000 nm, a surface area from 1 m²/g to 9 m²/g, and a porosityless than 0.020 m³/g. The composition has a methyl mercaptan odorsuppression value of less than 70 at 3 days as measured in accordancewith ASTM D5504-12. In an embodiment, the thermoplastic material is theolefin-based polymer.

As used herein, the term “film”, including when referring to a “filmlayer” in a thicker article (or a multilayer film structure), unlessexpressly having the thickness specified, includes any thin, flatextruded or cast thermoplastic article having a generally consistent anduniform thickness up to about 0.254 millimeters (10 mils). “Layers” infilms can be very thin, as in the cases of microlayers or nanolayers.

The film can be a monolayer film or a multilayer film. In an embodiment,the film (either monolayer film or multilayer film) has a thickness from5 microns, or 10 microns, 15 microns, or 20 microns, or 25 microns to 30microns, or 40 microns, or 50 microns, or 60 microns, or 70 microns, or80 microns, or 90 microns, or 100 microns, or 125 microns.

In an embodiment, the film is a blown monolayer film formed fromComposition 2, Composition 2 having an odor suppressant value less than70 at 3 days, the blown film having

(i) a Dart impact strength from 600 g, or 700 g, or 750 g to 775 g, or800 g, or 825 g; and/or

(ii) an Elmendorf tear strength from 300 gf, or 350 gf, or 375 gf to 400gf, or 425 gf.

F. Multilayer Film

In an embodiment, the film is a multilayer film having at least two, orthree, or four, or five, or six, or seven, or eight, or nine to 10, or11, or 12, or 13, or 14, or 15 or more layers. Some methods, forexample, used to construct the multilayer film include cast co-extrusionor blown co-extrusion methods, adhesive lamination, extrusionlamination, thermal lamination, and coatings such as vapor deposition.Combinations of these methods are also possible.

The multilayer film may include a core layer, one or more adhesivelayers, one or more inner layers, and two surface layers (also known asskin layers, or innermost layer and outermost layer). The presentcomposition (thermoplastic polymer and odor suppressant) may beincorporated into one, some, or all of the foregoing layers. Forexample, the odor suppressant may be a component of the (i) core layer;and/or (ii) the adhesive layer(s); and/or (iii) the inner layer(s);and/or the surface layer(s).

Nonlimiting examples of materials suitable for the core layer include abarrier material, ethylene-based polymer, propylene-based polymer, andcombinations thereof.

Nonlimiting examples of materials suitable for the adhesive layer(s)include functionalized ethylene-based polymers such as ethylene-vinylacetate (“EVA”), polymers with maleic anhydride-grafted to polyolefinssuch as any polyethylene, ethylene-copolymers, or polypropylene, andethylene acrylate copolymers such an ethylene methyl acrylate (“EMA”),glycidyl containing ethylene copolymers, propylene and ethylene basedolefin block copolymers (OBC) such as INTUNE™ (PP-OBC) and INFUSE™(PE-OBC) both available from The Dow Chemical Company, and blendsthereof.

Nonlimiting examples of materials suitable for the inner layers (whenpresent) include ethylene-based polymer, propylene-based polymer,polystyrene, nylon, polyester, and combinations thereof.

Nonlimiting examples of materials suitable for the surface layersinclude ethylene-based polymer, propylene-based polymer, nylon,polyester, and combinations thereof.

In an embodiment, the multilayer film with core layer, one or moreadhesive layer(s), optional inner layer(s), and surface layers has athickness from 5 microns, or 10 microns, or 15 microns, or 20 microns,or 25 microns to 30 microns, or 40 microns, or 50 microns, or 60microns, or 70 microns, or 80 microns, or 90 microns, or 100 microns, or125 microns.

In an embodiment, multilayer film includes a core layer that is abarrier layer. The barrier layer contains a barrier material.Nonlimiting examples of suitable materials for the barrier materialinclude ethylene-vinyl acetate copolymer (EVA), ethylene vinyl alcoholcopolymer (EVOH), copolymers of vinylidene chloride and methyl acrylate,methyl methacrylate or vinyl chloride (e.g., SARAN resins available fromThe Dow Chemical Company); vinylethylene vinyl alcohol (EVOH), and metalfoil (such as aluminum foil) and combinations thereof.

In an embodiment, the barrier layer is halogen-free. The odorsuppressant may be a component of the barrier layer.

In an embodiment, the multilayer film has at least two layers. The firstlayer is composed of an LLDPE. The LLDPE is an ethylene/C4-C8 α-olefincopolymer with melt index (12) from 0.5 g/10 min to 1.0 g/10 min, an110/12 ratio from 7 to 8, and a density from 0.916 g/cc to 0.920 g/cc.The second layer is composed of a second ethylene-based polymerdifferent than the LLDPE in the first layer. The odor suppressant can bepresent in (i) the first layer, (ii) the second layer, or (iii) both thefirst layer and the second layer. In a further embodiment, the odorsuppressant is present in the first layer containing the LLDPE.

The multilayer film may include an optional third layer. The optionalthird layer may be any thermoplastic polymer as previously disclosedherein. In an embodiment, the third layer is a barrier layer sandwiched,or otherwise disposed between, the first layer and the second layer. Themultilayer film with at least two layers, the first layer composed ofLLDPE and the odor suppressant, and optional third layer is hereafterreferred to as multilayer film1.

In an embodiment, multilayer film1 is a garbage receptacle liner,otherwise known as a “trash liner.” The trash liner includes a firstsidewall and an opposing second sidewall overlaying and joined to thefirst sidewall to provide an interior volume therebetween. The sidewallsare made from multilayer film1. The first and second sidewalls aretypically rectangular in shape and may be joined along a first sideedge, a second side edge, and a closed bottom edge that extends betweenthe first and second side edges. The side edges may be joined togetherby any suitable means such as heat sealing.

For accessing the interior volume to insert items, such as, refuse orgarbage, the top edges of the first and second sidewalls remainun-joined to define an opening located opposite the closed bottom edge.

When items are placed in the trash liner, the top edges of the first andsecond sidewalls may be folded over the rim of the receptacle. To closethe opening of the trash liner, the trash liner bag is typically fittedwith a draw tape. To accommodate the draw tape, the first top edge ofthe first sidewall is folded back into the interior volume and attachedto the interior surface of the sidewall to form a first hem. Similarly,the second top edge of the second sidewall is folded back into theinterior volume and attached to the second sidewall to form a secondhem. It is understood that the top edges may be folded to the exteriorand attached to the exterior of the sidewalls.

In an embodiment, the multilayer film contains three or more layers(i.e., one or more core layer(s) and two surface layers), and at leastone core layer that is a barrier layer. The barrier material for thebarrier layer may be any barrier material as previously disclosedherein. The multilayer film with three or more layers, one layer being abarrier layer is hereafter referred to as multilayer film2.

In an embodiment, multilayer film2 includes one or more adhesive layersin addition to the barrier layer and the surface layers. The odorsuppressant may be present in (i) the barrier layer, and/or (ii) one orboth surface layers, and/or (iii) the adhesive layer(s), and (iv) anycombination of (i)-(iii).

In an embodiment, multilayer film2 includes one or more adhesive layersand one or more inner layers in addition to the barrier layer and thesurface layer. The odor suppressant may be present in (i) the barrierlayer, and/or (ii) one or both surface layers, and/or (iii) the adhesivelayer(s), and/or (iv) the inner layer(s), and (v) any combination of(i)-(iv).

In an embodiment, the multilayer film2 is formed into an ostomy bag.

G. Additives

Any of the foregoing films (or foregoing film layers) may include one ormore optional additives. Nonlimiting examples of suitable additivesinclude opacifying agents, pigments, colorants, slip agents,antioxidants, anti-fog agents, anti-static agents, anti-block agents,fillers, moisture barrier additives, gas barrier additives andcombinations thereof. Such additives may be used in effective amounts,which vary depending upon the property required. Slip agents,antiblocking agents, anti-static agents, antioxidants and anti-fogagents are particularly effective when used in the surface layer(s).

In an embodiment, the film includes a pigment and/or a colorant. Pigmentand colorant are typically added to polymers to impart opacity and, insome cases, particular color to the resulting films. Nonlimitingexamples of suitable pigments and colorants include iron oxide, carbonblack, colored pigments, aluminum, titanium dioxide (TiO₂), calciumcarbonate (CaCO₃), polybutylene terephthalate, talc, and combinationsthereof.

In an embodiment, the film includes a slip agent. Nonlimiting examplesof suitable slip agents include erucamide, polymethyl methacrylate(PMMA), and polydialkyl siloxane.

In an embodiment, the film includes an anti-oxidant. Nonlimitingexamples of suitable anti-oxidants include phenolic anti-oxidants, suchas IRGANOX™ 1076 (commercially available from Ciba-Geigy Company ofSwitzerland) and phosphite anti-oxidants such as IRGANOX™ 168 (alsocommercially available from Ciba Geigy Company of Switzerland).

In an embodiment, the film includes an anti-static agent. Nonlimitingexamples of suitable anti-static agents include alkali metal sulfonates,polyether-modified polydiorganosiloxanes, polyalkylphenylsiloxanes, andtertiary amines.

In an embodiment, the film includes a filler and/or an anti-blockingagent. Nonlimiting examples of anti-blocking agents include finelydivided inorganic solid materials such as silica, fumed silica,diatomaceous earth, calcium carbonate, calcium silicate, aluminumsilicate, kaolin, talc, bentonite, clay and pulp.

All other factors being equal the more ZnO present in a polymericcomposition, the greater the odor suppression capability. ZnO particlesurface area and gaseous odor suppression follow a direct correlationwhereby the larger the surface area of the ZnO particle, the greater theodor suppression capacity. Similarly, ZnO particle porosity and gaseousodor suppression also follow a direct correlation whereby the greaterthe porosity of the ZnO particle, the greater the odor suppressioncapacity.

ZnO load and ZnO particle morphology influence processability andphysical properties when present in a polymer matrix. High surface areaZnO particles (i.e., ZnO particles with surface area of 10 m²/g orgreater) tend to increase the viscosity of the matrix polymer in whichthe ZnO particles are embedded, which may degrade polymer meltprocessing. High surface area ZnO particles also inhibit uniformdispersion of the ZnO particles into a polymeric matrix. Moreover, largeZnO particles (ZnO particles with average diameter greater than 3microns) added to a polymer matrix are known to degrade polymer filmproperties. Large ZnO particles are problematic and often act asinitiation sites for cracks, tears, and crazing within a polymer matrix,degrading physical properties such as tear strength, elongation, andDart impact.

Surprisingly, films formed from the present composition (i.e.,Composition 1 and/or Composition 2) exhibits the same, or better, odorsuppression capability without compromising processability and withoutcompromising film properties. Applicant discovered the ZnI/O workssynergistically with the ZnO to improve odor suppression with less totalzinc (and less ZnO) compared to ZnO-polymer matrix systems containingmore ZnO. ZnI/O alone has little, or no, odor suppression capability.The ability of ZnI/O to synergistically improve odor suppression whencombined with ZnO particles with D50 100-3000 nm, surface area of 1-9m²/g and porosity less than 0.02 m³/g is unexpected.

By way of example, and not limitation, some embodiments of the presentdisclosure will now be described in detail in the following Examples.

EXAMPLES

Materials used in the examples are provided in Table 1 below.

TABLE 1 Material/ Description Properties Source DOWLEX ™ LLDPE,ethylene/octene copolymer; The Dow 2085G density = 0.92 g/cc; MIChemical (LLDPE) 0.85 g/10 min, Tm = 121.6° C. Company AMPLIFY IO ™Metal salt of zinc ion and ethylene/ The Dow 3701 acrylic acidcopolymer; Chemical (ZnI/O) density = 0.940 g/cc; Tm = Company 95° C.;MI = 5.2 g/10 min Agility 1021 LDPE; density = 0.920 g/cc; The Dow Tm =108.1° C.; MI = Chemical 1.85 g/10 min Company ZNO 800HSA ZnO D50particle size 3000 nm; Zinc Oxide, Zinc Oxide density = 5.61 g/cc; LLC(ZnO-1) Porosity 0.0131 g/m³, powder surface area 4.46 m²/g Zinc OxideZnO ZnO D50 particle size 500 nm; 500 nm (US MicroPowder, density = 5.61g/cc; Research ZnO, 99.9+% Porosity 0.008 m³/g, Nanomaterials) ZincOxide surface area 3.36 m²/g (ZnO-2) powder Zoco102 ZnO D50 particlesize 200 nm; Zochem inc. Zinc Oxide density = 5.61 g/cc; (ZnO-3)Porosity 0.012 m³/ powder g, surface area 4.4 m²/g Ampacet 110069 70 wt% TiO₂ Ampacet White PE MB in Carrier Resin LLDPE Corporation Titaniumdioxide (MI 2.3, d- 0.917 g/cc) (TiO₂) Masterbatch Specific Masterbatchgravity: 2.03

1. Films

The compositions of CS1-CS8 and IE1-IE8 are formed into a blown film bycompounding the LLDPE, the ZnO (when present), the ZnI/O (when present),and the TiO₂ (when present) in a 30 mm co-rotating, intermeshingCoperion Werner-Pfleiderer ZSK-30 (ZSK-30) twin screw extruder. Theextruder is operated at 40 lbs per hour under a screw rotation speed of250 rpm. Die pressure is maintained between 450 to 500 psi. Melttemperature is maintained near 240° C. Nitrogen purging is applied atthe feed throat. A standard water bath is used for cooling and a strandcut pelletizer is employed to product the pellets. Pellets were storedin ambient conditions prior to use.

The blown film is a single layer film.

TABLE 2 Blown film line process parameters Films Films withoutcontaining Parameter Units TiO₂ MB TiO₂ MB Takeoff m/min 15 15 Layflatcm 23.5 23.5 Frostline cm 14 14 B.U.R ratio 2.5 2.5 Die gap mm 2.0 2.0Melt temperature - Ext. A ° C. 218 218 Melt temperature - Ext. B ° C.226 226 Melt temperature - Ext. C ° C. 215 215 RPM - Ext. A rpm 51 51RPM - Ext. B rpm 50 50 RPM - Ext. C rpm 32 32 Total Output kg/hr 8.8 8.8Film Total Thickness mm 0.023 0.056

In Table 3 below, Dart Impact and tear strength values are for filmswith 0.023 mm thickness. Films with TiO₂ MB have 0.056 mm thickness,with exception to the CS7 film having a thickness of 0.023 mm.

2. Odor Suppression

Odor suppression values are measured over 192 hours (8 days) inaccordance with ASTM D5504-10 as described above in the odor suppressiontest method.

Film strips with a mass of 1 g (1 cm×30 cm and thickness in Table 2) ofcontrol samples (CS) CS1-CS8 and inventive examples (IE) IE1-IE8 areplaced in Tedlar® bags filled with methyl mercaptan and helium gascarrier as described in the odor suppression test method, disclosedabove.

Comparative samples (CS), CS1-CS8 are prepared. CS1 is a control samplewith DOWLEX 2085 and CS2 is a control sample 93 wt % LLDPE and 7 wt %TiO₂ masterbatch.

CS3 and CS4, are blends of ZnO and LLDPE (control) with varying amountof ZnO in the blend.

CS5, CS6, CS7 are blends of zinc ionomer and LLDPE (control) withvarying amount of zinc ionomer in the blend.

CS8 is a blend of ZnO, TiO₂ and LLDPE (control).

IE1-IE8 are inventive examples of the present composition composed ofLLDPE and odor suppressant composed of ZnO and ZnI/O.

The odor suppression values (OSV) for CS1-CS8 and IE1-IE8 are providedin Table 3 below.

TABLE 3 Methyl Mercaptan Odor Suppression Values and Blown FilmProperties Tear Avg Sample Composition Day 1 Day 2 Day 3 Day 4 Day 5 Day8 (gf) Dart (g) CS 1 7% wt % TiO₂ MB 94 77 94 73 80 89 308 588 (control)93 wt % LLDPE CS 2 100% LLDPE 2085 100 100 100 100 100 100 337 600(control) CS3 5 wt % ZnO-2 (500 nm) 78 89 81 70 66 68 341 624 95 wt %LLDPE CS4 5 wt % ZnO-1 (3000 nm) 82 99 87 66 70 59 403 588 95 wt % LLDPECS5 10 wt % Zn-I/O 116 105 114 90 92 117 263 653 90 wt % LLDPE CS6 5 wt% Zn-I/O 104 102 105 81 88 93 260 683 95 wt % LLDPE CS7 5 wt % TiO₂ MB102 91 92 83 77 89 223 653 5 wt % Zn-I/O 90 wt % LLDPE IE1 5 wt % ZnO-2(500 nm) 37 54 56 47 47 52 337 810 5 wt % Zn-I/O 90 wt % LLDPE IE2 5 wt% ZnO-1 (3000 nm) 72 61 67 n/t n/t n/t 420 773 5 wt % AMPLIFY I/O 370190 wt % LLDPE CS8 5 wt % ZnO-3 (200 nm) 93 n/t 93 n/t n/t n/t 5 wt %LDPE 7 wt % TiO₂ MB IE3 5 wt % ZnO-1 (3000 nm) 76 n/t 37 n/t n/t n/t 5wt % AMPLIFY IO 7 wt % TiO₂ MB IE4 5 wt % ZnO-2 (200 nm) 68 n/t 28 n/tn/t n/t 5 wt % AMPLIFY IO 7 wt % TiO₂ MB IE5 1.25 wt % ZnO-3 (200 nm) 77n/t 66 n/t n/t n/t 1.25 wt % AMPLIFY IO 7% wt % TiO₂ MB IE6 2.5 wt %ZnO-3 (200 nm) 74 n/t 54 n/t n/t n/t 2.5 wt % AMPLIFY IO 7% wt % TiO₂ MBIE7 3.75 wt % ZnO-3 (200 nm) 95 n/t 65 n/t n/t n/t 1.25 wt % AMPLIFY IO7% wt % TiO₂ MB IE8 1.25 wt % ZnO-3 (200 nm) 73 n/t 55 n/t n/t n/t 3.75wt % AMPLIFY IO 7 wt % TiO₂ MB *TiO₂ MB-titanium dioxide masterbatch 70wt % TiO₂ powder in 30 wt % LLDPE carrier, added for white color n/t-nottested

In Table 3, CS3-CS4 (ZnO only, at 5 wt %) demonstrate that ZnO only atsmall load (5 wt %) exhibits only a small degree of odor suppression at3 days (OSV 81, 87 respectively).

CS5-CS6 show ZnI/O only has no ability to suppress odor (114, 105respective OSV at 3 days).

CS8 shows that with ZnI/O blended with TiO₂ has only a small odorsuppression capability (OSV 92 at 3 days).

IE1-IE8 each show significant odor suppression capability (IE1, IE2 OSV56, 67 respectively at 3 days). For example, the ability of IE1 and IE2to provide greater odor suppression (respective OSV: 56, 67) than CS4(OSV: 87) is unexpected. Bounded by no particular theory, the ZnO andZnI/O work synergistically to improve the odor suppression ability ofZnO. Further unexpected is the discovery that ZnI/O, which alone, is anineffective odor suppressant, works synergistically with ZnO to improveodor suppression. Applicant discovered that odor suppression improves byblending ZnO with ZnI/O as opposed to increasing only the amount of ZnOin the absence of the zinc ionomer.

FIG. 1 is an SEM image of CS3 (5 wt % ZnO, D50=300 nm) blended in 95 wt% LLDPE (DOWLEX 2085G). FIG. 1 shows the ZnO particles dispersed in theLLDPE matrix phase. FIG. 2 is an SEM image of IE1 (5 wt % ZnO/5 wt %ZnI/O blended in 90 wt % LLDPE).

The SEM image of FIG. 2 shows the ZnI/O is a separate phase from thebulk LLDPE, and that the ZnO particles are encapsulated in the ZnI/Ophase to form domains of ZnO embedded in the ZnI/O. Bounded by noparticular theory, it is believed the formation of the ZnI/O—ZnO domainscontributes to accelerated diffusion of odor molecules. The ZnI/O ismore permeable to polar gasses (i.e., sulfur-based gasses, such asmethyl mercaptan). The permeability of the ZnI/O facilitates theinteraction of the odorous gas with the ZnO, contributing to thesuppression of odor.

The SEM image of FIG. 2 shows that the ZnI/O surrounds, and encapsulatesthe ZnO particles. The ZnI/O prevents cavitation at the polymer-particleinterface and prevents the rupture of the overall polymer. The ZnI/O—ZnOdomains do not create initiation sites.

In Table 3, films CS1 through CS8 each exhibit a Dart impact strengthless than 700 g whereas films IE1 and IE2 each exhibit Dart impactstrength greater than 700 g and greater than 750 g (respective Dartimpact values 810 g, 773 g).

Table 3 shows that the physical properties of Dart impact strength, forIE1 and IE2 are either maintained or improved when the present odorsuppressant (ZnO and ZnI/O) is used compared to film containing ZnOalone. Indeed, IE1 and IE2 show improvement for all film properties(Dart impact, tear) compared to the unfilled film sample of control filmCS1.

Applicant surprisingly discovered that the present odor suppressant(ZnO—ZnI/O) enables effective odor suppression using less total zincutilizing ZnO particles with D50 100-3000 nm, surface area 1 m²/g-9m²/g, and porosity less than 0.020 m³/g while simultaneously yieldingblown film with improved Dart impact strength (i.e., Dart impactstrength of 600 g and greater, or 700 g and greater). The ability toimprove odor suppression with less zinc by way of the presentcomposition and odor suppressant while maintaining and improving filmproperties is unexpected.

It is specifically intended that the present disclosure not be limitedto the embodiments and illustrations contained herein, but includemodified forms of those embodiments including portions of theembodiments and combinations of elements of different embodiments ascome within the scope of the following claims.

1. A film comprising: a composition comprising (A) from 85 wt % to 99 wt% of a thermoplastic polymer; (B) from 15 wt % to 1 wt % of an odorsuppressant comprising a blend of: (i) particles of zinc oxide, theparticles having a D50 particle size from 100 nm to 3000 nm, a surfacearea from 1 m²/g to 9 m²/g, and a porosity less than 0.020 m³/g; (ii) azinc ionomer, and the composition has a methyl mercaptan odorsuppression value of less than 70 at 3 days as measured in accordancewith ASTM D5504-12.
 2. The film of claim 1 wherein the thermoplasticpolymer is an olefin-based polymer.
 3. The film of claim 2, wherein theolefin-based polymer is an ethylene-based polymer to the exclusion ofother polymers.
 4. The film of claim 3, wherein the ethylene-basedpolymer is LLDPE.
 5. The film of claim 1 wherein the zinc ionomer is azinc salt of a polymer selected from the group ofethylene/methyl-methacrylic acid, ethylene/vinyl acrylic acid,ethylene/methacrylate, ethylene/n-butyl acrylic acid, and ethyleneacrylic acid.
 6. The film of claim 1, wherein the zinc ionomer is a zincsalt of an ethylene/acrylic acid copolymer.
 7. The film of claim 1,wherein the weight % ratio between zinc oxide (Bi) to zinc ionomer (Bii)is 3:1 to 1:7 based on total weight of the odor suppressant.
 8. The filmof claim 7 wherein the weight % ratio between B(i) to B(ii) is from 1:3to 1:7 based on total weight of the odor suppressant.
 9. The film ofclaim 8 wherein the odor suppressant is present in an amount from 1 wt %to 10 wt % based on total weight of the composition.
 10. The film ofclaim 8, wherein the particles of zinc oxide (Bi) have a D50 particlesize from 100 nm to 3000 nm; a surface area from 1.0 m²/g to 6.0 m²/g; aporosity from 0.005 m³/g to 0.015 m³/g and the composition has a methylmercaptan odor suppression value of less than or equal to 55 at 3 days.11. The film of claim 1 wherein film comprises from 0.5 wt % to 6.0 wt %total zinc.
 12. The film of claim 11 wherein the film is a single layerblown film and the film has a Dart impact strength greater than 600 g.13. The film of claim 1 wherein the film comprises a continuous-phasecomposed of the ethylene-based polymer and a discontinuous-phasecomposed of domains, the domains composed of the zinc oxide particles(Bi) embedded in the zinc ionomer (Bii).
 14. The film of claim 13wherein the domains have an average diameter from 500 nm to 10,000 nm.